I've just bought 2 download add-on airport scenery packs, both are Aerosoft products, for my FSX Steam.  One Manchester and the other Heathrow.  The Manchester files unzipped and installed without trouble right into the FSX scenery database without me even 'adding' it to the list of scenery files.  Heathrow just won't install (although it is there in the Aerosoft folder) although I've deleted and redownloaded it twice. Has anyone any idea whether this is an FSX problem, or how I could get FSX to recognise it?  Any help much appreciated.

I use FSX:SE and have the Heathrow airport from Aerosoft.  I'm not sure this is a fix for you, but on several occasions I've had success auto-installing to FSX when FSX:SE should have worked.

OK, thank you Pete, I'll try that.  What's got me flumoxed is why the Manchester add-on (downloaded immediately after) should appear in the same Aerosoft folder in FSX but is not visible in the scenery 'manager' part of the FSX settings.  Mabe I should delete manchester, reload it, and see where it goes and how it gets there!!  Perhaps I should download / 'save' and make sure I'm offline before installing?

Aerosoft have also advised I reinstall using FSX and not FSX-SE as the sim.  That has worked.